Focal plane shutter



March 26, 1968 R. NoACK ETAL 3,374,722

FOCAL PLANE SHUTTER Filed June ll, 1955 /M/E/v ToRs fam/@MM A TTORNEY 3,374,722 FOCAL PLANE SHUTTER Rolf Noack and `Iohannes Weise, Dresden, Germany, assignors to Veb Pentacon Dresden Kameraund Kinowerke, Dresden, Germany Filed June 11, 1965, Ser. No. 463,312 5 Claims. (Cl. 95-60) The invention relates to a photographic focal plane shutter having opening and closing discs, which successively open and close the image aperture at a time interval determinable by an escapement. y

Known shutters of this kind have gearings placed between the drive springs and the opening and closing discs for the drive of the opening and closing discs, the assembly of which gearings is quite complicated and very liable to troubles on account of the number of moving parts.

'The aim of the invention is a simple assembly of the drive mechanism for the opening and closing discs.

According to the invention this is achieved due to the fact that there is provided a pair of rotatably mounted double-armed levers, of which each lever comprises 'a toothed Segment arm and a drive arm connected with the end of the drive spring, one lever as opening lever meshing with a pinion of the opening discand the other lever as closing lever meshing with a pinion of the closing disc. The closing lever expediently comprises an escapement dog, in the path of which there is arranged the escapement lever of an escapement mechanism. In order to facilitate simultaneous blocking of both levers, the opening lever and the closing lever are preferably in forceeffected connection with one another by means of the closing spring. The opening lever and the closing lever can also be coaxially mounted. In order to achieve a selfcontained constructional unit for the new foe-al plane shutter, the opening disc and the closing disc are expediently mounted coaxially between two plates; between the opening disc and the closing disc there is provided a guide plate which prevents mutual hindrance of opening disc and closing disc. The details of the invention may be seen from an illustrated and described example of embodiment.

The opening disc 4 and the closing disc 5 are rotatably mounted about the spindle 3 between the plates 1 and 2. The pinion 6 is rigidly connected with the opening disc 4 and the pinion 7 is rigidly connected with the closing disc 5. The toothed segment arm 8 of the opening lever 9 meshes with the pinion 6 and the toothed segment arm 10 of the closing lever 11 is in engagement with the pinion 7. The opening lever 9 has a catch tab 12 which can be grasped by the release lever 13. Moreover the opening lever 9 has -a nose 14 in the path of which there is arranged a coupling tab of the closing lever 11. Furthermore on the opening lever 9 there is secured the opening spring 16 and on the closing lever 11 there is secured the closing spring 17. Between the opening disc 4 and the closing disc 5 there lies the guide plate 18, which has a circular opening 19. Image apertures 20 and 21 aligned with one another are cut into the plates 1 and 2.

On the closing lever 11 there is provided an escapement dog 22, into the path of which there extends the escapement lever 23. The escapement lever 23 is geared through the toothed segment 24 with the escapement mechanism 2S, 26, 27. A control pin 28 of the toothed segment 24 can be pivoted by the control cam 29 of a 3,374,722 Patented Mar. 26, 1968 time-setting member into different initial positions, so that different exposure times are obtained.

l The manner of operation of the new shutter is as folows:

When the shutter is cocked the individual components assume positions according to the illustration. If the release 13 is operated against its spring 31, the opening spring 16 and the closing spring 17 can rotate the opening lever 9 and the closing lever 11 in the clockwise direction. Through the segment arm 8 the opening lever 9 drives the opening disc 4 in the counter-clockwise direction, s0 that the opening disc 4 springs out of the region of the image apertures 20 and 21. The return of the opening lever 9 into the rest position is limited by a stop 32. The running otf of the closing lever 11 is retarded in comparison therewith according to the measure of the preset escapement mechanism, as a result of the escapement lever 23 lying in the path of the escapement dog 22. Then the closing lever 11 permits the closing disc 5 to follow the opening disc 4, which comes to a halt in the region of the image apertures 20 and 21. In the rest position the opening disc 9 and the closing disc 11 are caught by brake springs 35.

For the cocking of the shutter the drive arm 33 of the opening lever 9 is grasped and rotated in the counterclockwise direction. Through the nose 14 the drive arm 34- of the closing lever 11 is grasped by the coupling tab 15 and also rotated in a counter-clockwise direction. At the end of the cocking operation the release lever 13 drops behind the catch tab 12 and blocks both the opening lever 9 and the closing lever 11.

We claim:

1. A photographic focal plane shutter having rotating opening and closing discs, which successively open and close the image aperture at a time interval determinable by an escapement mechanism, comprising a pair of rotatably mounted double-armed levers, each of which comprises a toothed segment arm having a drive arm connected with the end of a drive spring, the one lever as opening lever meshing with a pinion of the opening disc and the other lever as closing lever meshing with a pinion of the closing disc.

2. A photographic focal plane shutter according t0 claim 1, wherein the closing lever comprises an escapement dog in the path of which there is arranged the escapement lever of an escapement mechanism.

3. A photographic focal plane shutter according to claims 1 and 2, wherein the opening lever and the closing lever are in force-effected connection with one another by means of the closing spring.

4. A photographic focal plane shutter according to claim 1, wherein the opening lever and the closing lever are co-axially mounted.

5. A photographic focal plane shutter according to claims 1 to 3, wherein the opening disc and the closing disc are co-aXially mounted between two plates and in that a guide plate is provided between the opening disc and the closing disc.

References Cited UNITED STATES PATENTS 547,541 10/1895 Esmond 95-59 JOHN M. HORAN, Primary Examiner. 

1. A PHOTOGRAPHIC FOCAL PLANE SHUTTER HAVING ROTATING OPENING AND CLOSING DISCS, WHICH SUCCESSIVELY OPEN AND CLOSE THE IMAGE APERTURE AT A TIME INTERVAL DETERMINABLE BY AN ESCAPEMENT MECHANISM, COMPRISING A PAIR OF ROTATABLY MOUNTED DOUBLE-ARMED LEVERS, EACH OF WHICH COMPRISES A TOOTHED SEGMENT ARM HAVING A DRIVE ARM CONNECTED WITH THE END OF A DRIVE SPRING, THE ONE LEVER AS OPENING LEVER MESHING WITH A PINION OF THE OPENING DISC AND THE OTHER LEVER AS CLOSING LEVER MESHING WITH A PINION OF THE CLOSING DISC. 